I was diagnosed with fibromyalgia about 3 years ago. If you don't have it lemme just say, it's awful.
Everyone I went to had no answer other than pain killers and yoga.
Well my OCD likes to solve problems, so I obsessed about it and consumed as much info as I could online until I found my own personal holy grail.
It turned out the cause was a small intestinal bacterial overgrowth (which is by the way INCREDIBLY difficult, in fact near impossible to test for).
I'm now on Linzess 290 and eat things like pumpkin to relieve of any blockage. Laxatives can help, but try not to be too reliant as they can cause a lot of issues including your intestines basically shutting down. I took soy out of my diet as too much can cause digestive issues, and sugar is out as well. (other than natural sugars)
All pain is gone
All brain fog is gone
All fatigue is gone
The bacteria basically caused a blockage which made my body and brain go nuts with toxins making my life a living hell.
I really hope this helps some here find refief.